Power architecture for a vehicle such as an off-highway vehicle

ABSTRACT

The present disclosure relates to a power distribution architecture for an off-road vehicle. The power distribution architecture includes a work circuit and a propel circuit and is configured for facilitating bi-directional power exchange between the work circuit and the propel circuit.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.16/459,162, filed Jul. 1, 2019; which claims the benefit of U.S.Provisional Patent Application No. 62/697,255, filed Jul. 12, 2018,which applications are hereby incorporated by reference in theirentireties.

TECHNICAL FIELD

The present disclosure relates generally to power architectures forvehicles. More particularly, the present disclosure relates to powerarchitectures that distribute power electrically, hydraulically, andmechanically.

BACKGROUND

In a typical off-highway (i.e., off-road) vehicle, the engine of thevehicle generally powers both the propel circuit, which conventionallyincludes a hydraulic or mechanical transmission, and the work circuit,which is conventionally hydraulically powered. Electric hybrid off-roadvehicles have been developed, but improvements are needed in this area.

SUMMARY

Aspects of the present disclosure relate to power architectures suitablefor use in vehicles such as off-road vehicles. In certain examples, thepower architectures include integrated hybrid and electrical powerarchitectures. In certain examples, the power architectures can beconfigured to allow for bi-directional power exchange optimizationbetween a work circuit and a propel circuit of a vehicle such as anoff-road vehicle. In certain examples, the power architectures can allowfor optimized power exchange between the work circuit and the propelcircuit thereby allowing recaptured energy to be more effectivelyutilized while also allowing batteries for storing energy to bedownsized by optimizing the real-time use of recovered energy. Certainaspects of power architectures in accordance with the principles of thepresent disclosure allow electric motors to be downsized by using powerarchitectures where power is derived both hydraulically (e.g., from acommon pressure rail) and electrically (e.g., from a common electricbus). Certain aspects of the present disclosure relate to architectureswhich hybridize both the work circuit and the propel circuit to enhanceefficiency thereby reducing energy consumption and providing fuelsavings.

A variety of additional inventive aspects will be set forth in thedescription that follows. The inventive aspects can relate to individualfeatures and to combinations of features. It is to be understood thatboth the forging general description and the following detaildescription are exemplary and explanatory only and are not restrictiveof the broad inventive concepts upon which the examples disclosed hereinare based.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the description, illustrate several aspects of the presentdisclosure. A brief description of the drawings is as follows:

FIG. 1 shows a first power distribution architecture in accordance withthe principles of the present disclosure for powering a propel circuitand a work circuit of a vehicle such as an off-road vehicle;

FIG. 2 illustrates a second power distribution architecture inaccordance with the principles of the present disclosure for powering apropel circuit and a work circuit of a vehicle such as an off-roadvehicle;

FIG. 3 shows a third power distribution architecture in accordance withthe principles of the present disclosure for powering a propel circuitand a work circuit of a vehicle such as an off-road vehicle;

FIG. 4 shows a fourth power distribution architecture in accordance withthe principles of the present disclosure for powering a propel circuitand a work circuit of a vehicle such as an off-road vehicle; and

FIG. 5 depicts a fifth power distribution architecture in accordancewith the principles of the present disclosure for powering a propelcircuit and a work circuit of a vehicle such as an off-road vehicle.

DETAILED DESCRIPTION

FIG. 1 illustrates a first power distribution architecture 20 inaccordance with the principles of the present disclosure fordistributing, managing, optimizing, exchanging and blending power in avehicle such as an off-road vehicle. The power distribution architecture20 includes a propel circuit 22 and a work circuit 24. The propelcircuit 22 is adapted to power vehicle propulsion elements such astracks or wheels of a vehicle such as an off-road vehicle. In certainexamples, the propel circuit 22 interfaces with a transmission ordrivetrain that transfers power to the propulsion elements. The workcircuit 24 provides power to various working elements or actuators ofthe vehicle. Example actuators can include hydraulic cylinders andhydraulic motors. As depicted, the actuators can include an actuator 26for providing tilt functionality, actuators 27 for providing liftfunctionality (e.g., lifting of a boom or arm) actuators 28 for steeringfunctionality and an actuator 29 for auxiliary functionality. In certainexamples, the work circuit can also power other types of actuators suchas hydraulic motors/pumps that may be used to provide otherfunctionality such as swing-drive functionality. It will be appreciatedthat swing-drive functionality relates to the ability to swing or rotatea cab or operator station of a work vehicle relative to a main chassisof the work vehicle. Typically, the cab or operator stationrotates/swings in concert with a work element such as a boom, arm,shovel, lift, blade or the like. Aspects of the present disclosurerelate to overlaying (e.g., merging, integrating, combining, etc.)hydraulic and electric power distribution architectures in one circuitso that blended power derived from both a hydraulic power source and anelectric power source can be used to drive an active component (e.g., ahydraulic cylinder, a hydraulic pump/motor, an electric motor/generator,etc.) of the vehicle.

Referring still to FIG. 1, the first power distribution architecture 20includes a prime mover 34 such as an internal combustion engine (e.g., aspark ignition engine or a diesel engine), a fuel cell or the like. Inthe example of FIG. 1, the prime mover 34 powers an electrical generator36 for providing electrical power to a propulsion electricmotor/generator 38. The electrical generator 36 is electricallyconnected to a traction inverter 39 of the propulsion electricmotor/generator 38. The traction inverter 39 can include dual inverterfed motor drives. In certain examples, the traction inverter 39 canprovide alternating current (AC) to direct current (DC) electricalconversion. In the depicted example, the traction inverter 39 providesAC-DC conversion and then DC-AC conversion to drive the motor/generator.The AC-DC conversion enables the inverter to provide a DC voltage output43, and the DC-AC conversion allows AC to be used to be used to drivethe propulsion electric motor/generator 38. The propulsion electricmotor/generator 38 can be mechanically coupled to the propulsion system(e.g., drivetrain) of the vehicle. Thus, the propulsion electricmotor/generator 38 can be used to drive wheels or tracks of the vehicle.It will be appreciated that the propulsion electric motor/generator 38can be operated at relatively high voltages (e.g., 650 volts DC).

Referring still to FIG. 1, the DC voltage output 43 of the propulsionelectric motor/generator 38 is electrically connected to an electricalpower storage device such as a battery 40 and to a power distributionunit 42. The battery 40 is integrated as part of the propel powercircuit and preferably is a relatively high voltage battery whichoperates at a voltage higher than a corresponding battery 41 integratedas part of the work circuit 24. The battery 40 at the propel circuit 22is preferably larger than the battery 41 at the work circuit 24. Thepower distribution unit 42 can manage bi-directional power exchangebetween the propel circuit 22 and the work circuit 24. The powerdistribution unit 42 can include an on-board battery charger or chargersand can include a voltage converter or converters for providingelectrical voltage conversion (e.g., high voltage to low voltage DC-DCvoltage conversion). The power distribution unit 42 provides aninterface between the propel circuit 22 and the work circuit 24 and isconfigured such that the work circuit 24 can be operated at asubstantially lower voltage than the propel circuit 22 whileconcurrently facilitating bi-directional electrical power exchangebetween the work circuit 24 and the propel circuit 22. The propulsionelectric motor/generator 38 can output electrical power (e.g., from thetraction inverter 39) which can be stored at the battery 40 within thepropel circuit 22 or can be directed though the power distribution unit42 to the work circuit 24 for use in powering the actuators 26-29 or forstorage at the battery 41. At least a portion of the energy output fromthe propulsion electric motor/generator 38 can includerecovered/regenerated energy that is recovered from the propel circuit22 (e.g., energy recovered from braking). The propulsion electricmotor/generator 38 can receive electrical power from the battery 40.Additionally, electric power generated at the work circuit 24 or storedat the battery 41 can be routed through the power distribution unit 42to the propulsion electric motor/generator 38 and/or to the battery 40.

As indicated above, the power distribution unit 42 can be configured toenable optimized power exchange between the propel circuit 22 and thework circuit 24. Diagnostics and predicted optimization can be enabledby the power distribution unit 42. In certain examples, the battery sizeof batteries within the system can be reduced due to the real time powertransfer enabled by the power distribution unit 42 between the workcircuit 24 and the propel circuit 22. As indicated above, the powerdistribution unit 42 can include voltage conversion circuitry forproviding voltage conversion (e.g., a DC-DC voltage conversion) betweenthe work circuit 24 and the propel circuit 22. Typically, the voltage isconverted bi-directionally between the work circuit 24 and the propelcircuit 22 such that the voltage utilized by the work circuit 24 issubstantially lower than the voltage utilized by the propel circuit 22.In the depicted embodiment, the work circuit 24 has a DC electrical bus44 electrically coupled to the power distribution unit 42 fortransferring electrical power to and from the various electricalcomponents of the work circuit 24, for exchanging electrical powerbetween the various electrical components of the work circuit 24, andfor transferring electrical power between the various electricalcomponents of the work circuit 24 and the power distribution unit 42. Inone example, the DC electrical bus 44 can optionally have a voltage of48 volts, and the propel circuit 22 is optionally operated at 650 voltsDC.

The DC electrical bus 44 provides electrical power to separate dualpower electro-hydraulic motion control units 46 a-46 d respectivelyhydraulically coupled to each of the actuators 26-29. Thus, the DCelectrical bus 44 is an electrical power source for each of the dualpower electro-hydraulic motion control units 46 a-46 d. Each of the dualpower electro-hydraulic motion control units 46 a-46 d can include anelectric motor/generator 48 electrically coupled to the DC electricalbus 44. Each of the electric motor/generators 48 can include a motordrive 49 which may include a DC-DC integrated motor drive converter oran AC-DC integrated motor drive converter. Each of the dual powerelectro-hydraulic motor control units 46 a-46 d can also include ahydraulic motor/pump 50 mechanically coupled to the electricmotor/generator 48 (e.g., by a drive shaft). The dual powerelectro-hydraulic motion control units 46 a-46 d can preferably beconfigured for receiving both electrical power (e.g., from the DCelectrical bus 44) and hydraulic power (e.g., from a common pressurerail 55), and can each be configured to produce a blended power outputderived from the electrical and hydraulic power which can be used topower the actuators 26-29.

The dual power electro-hydraulic motion control units 46 a-46 d can alsobe configured direct power recovered from the actuators 26-29 duringover-running conditions to the DC electric bus 44 and/or the commonpressure rail 55. In certain examples, the electro-hydraulic motioncontrol units 46 a-46 d can be configured to convert hydraulic powerfrom the common pressure rail 55 into electrical power which is directedto the DC electrical bus 44. Electrical power transferred from theelectro-hydraulic motion control units 46 a-46 d to the DC electricalbus 44 can be used in real-time power sharing with the otherelectro-hydraulic motion control units 46 a-46 d, and/or can be storedat the battery 41, and/or can be directed through the power distributionunit 42 for use at the propel circuit 22. Further details about exampledual power electro-hydraulic motion control units suitable for use atthe work circuit 24 to drive actuators are disclosed by U.S. ProvisionalPatent Application Ser. No. 62/697,226 filed Jul. 12, 2018 which hasattorney docket number 15720.0545USP1 and is entitled Dual PowerElectro-Hydraulic Motion Control System.

Referring still to FIG. 1, the first power distribution architecture 20utilizes a power take-off 60 to mechanically transfer mechanical energyfrom the prime mover 34 to a hydraulic pump 62 used to pressurize thecommon pressure rail 55. An accumulator 64 for storing recovered energyand other energy is also hydraulically connected to the common pressurerail 55. The separate battery 41, which is preferably smaller than thebattery 40 at the propel circuit 22, is preferably electricallyconnected to the DC electrical bus 44 and configured for storingelectrical energy recovered by the dual power electro-hydraulic motioncontrol units 46 a-46 d. The common pressure rail 55 serves as ahydraulic power source for each of the dual power electro-hydraulicmotion control units 46 a-46 d. As depicted, the common pressure rail 55is fluidly connected to ports of the hydraulic pumps/motors 50 of thedual power electro-hydraulic motion control units 46 a-46 d.

FIG. 2 illustrates a second power distribution architecture 120 inaccordance with the principles of the present disclosure fordistributing, managing, optimizing, exchanging and blending power in avehicle such as an off-road vehicle. The second power distributionarchitecture 120 has the same configuration as the first powerdistribution architecture 20 except the power take-off 60 for drivingthe hydraulic pump 62 has been replaced with an electric motor/generator90. The electric motor/generator 90 is electrically powered by the DCvoltage output 43 from the traction inverter 39. In certain examples,the electric motor/generator 90 can include a motor drive 92 thatprovides DC-AC conversion. An electrical line 94 allows electrical powerto be transferred bi-directionally between the electric motor/generator90 and the propel circuit 22. The electrical line 94 can be electricallyconnected to the battery 40, the power distribution unit 42 and thetraction inverter 39. Other than the addition of the electrical line 94,power sharing and management between the work circuit 24 and the propelcircuit 22 can operate in the same way described with respect to thefirst power distribution architecture 20 of FIG. 1. In certain examples,the electrical generator 36 of the second power distributionarchitecture 120 is larger than the electrical generator 36 of the firstpower distribution architecture 20 since the electrical generator 36 ofthe second power distribution architecture 120 provides full power forboth the propel circuit 22 and the work circuit 24.

FIG. 3 shows a third power distribution architecture 220 in accordancewith the principles of the present disclosure for distributing,managing, optimizing, exchanging and blending power in a vehicle such asan off-road vehicle. It will be appreciated that the third powerdistribution architecture 220 has the same configuration as the secondpower distribution architecture 120 except the power distribution unit42 has been eliminated. Instead, the third power distributionarchitecture 220 includes an additional electric generator 96 powered bythe prime mover 34. The electric generator 96 provides electrical powerto the DC electrical bus 44 corresponding to the work circuit 24. Asdepicted, the electrical generator 96 provides electrical power to powerelectronics 98 such that an AC-DC converter that converts an AC inputfrom the electric generator 96 to a DC output provided to the DCelectrical bus 44. Preferably, the DC output provided to the DCelectrical bus 44 is substantially less than the DC output provided bythe traction inverter 39. In the example third power distributionarchitecture 220 of FIG. 3, the DC electrical bus 44 is separate orisolated from an electrical bus 102 connected to the traction inverter39. The electrical bus 102 is energized by the propulsion electricmotor/generator 38 (e.g., from the traction inverter 39) and iselectrically connected to the battery 40 and the motor drive 92 of theelectric motor/generator 90. Thus, the third power distributionarchitecture 220 of FIG. 3 utilizes separate electrical buses, while thepower architectures of FIGS. 1 and 2 use an electrical arrangement inwhich the buses are integrated or coupled together through the powerdistribution unit 42.

FIG. 4 shows a fourth power distribution architecture 320 in accordancewith the principles of the present disclosure for distributing,managing, optimizing and exchanging power in a vehicle such as anoff-road vehicle. The fourth power distribution architecture 320 has thesame configuration as the second power distribution architecture 120 ofFIG. 2 except the common pressure rail 55, the hydraulic pump 62 and theelectric motor/generator 90 have been eliminated. Thus, the fourth powerdistribution architecture 320 does not utilize blended hydraulic andelectrical power at the work circuit 24. It will be appreciated thatboth the propel circuit 22 and the work circuit 24 are electrified. Thepower distribution unit 42 enables the optimized power exchange betweenthe work circuit 24 and the propel circuit 22. The power exchangebetween the work circuit 24 and the propel circuit 22 is electrical. Atthe work circuit 24, the DC electrical bus 44 powers the electricalmotors/generators 48 which drive the hydraulic pumps/motors 50 used toprovide hydraulic power to the actuators 26-29. Thus, in the fourthpower distribution architecture 320 of FIG. 4, the electro-hydraulicmotion control units 46 a-46 d are not dual power, but instead onlyreceive electrical power which is converted to hydraulic power providedat the actuators 26-29. Because the common pressure rail 55 is not usedto assist in power exchange between the various components of theworking circuit 24, the low voltage battery 41 coupled to the electricbus 44 of the fourth distribution architecture 320 is preferably largerthan the low voltage batteries 41 used in the power distributionarchitectures 20, 120, 220 of FIGS. 1-3. It will be appreciated that byeliminating the hydraulic pump 62, pump losses and/or metering lossescan be eliminated from the work circuit 24. It will be appreciated thatbi-directional power exchange between the work circuit 24 and the propelcircuit 22 can operate in the same way described with respect to thebi-directional electrical power exchange of the first power distributionarchitecture 20 of FIG. 1.

FIG. 5 illustrates a fifth power distribution architecture 420 inaccordance with the principles of the present disclosure fordistributing, managing, optimizing, exchanging and blending power in avehicle such as an off-road vehicle. It will be appreciated that thefifth power distribution architecture 420 has the same basicconfiguration as the first power distribution architecture 20 of FIG. 1except propulsion of the vehicle is provided by a mechanicaltransmission 106 which mechanically extracts energy from the prime mover34 by a power take-off 110. Additionally, the prime mover 34 powers theDC electrical bus 44 of the work circuit 24 in the same manner describedwith respect to the third power distribution architecture 220 of FIG. 3.In the fifth power distribution architecture 420, only one electricalbus (e.g., the DC electrical bus 44 for energizing the work circuit 24)is utilized and power for driving propulsion of the vehicle as well asfor driving the hydraulic pump 62 for pressurizing the common pressurerail 55 is provided mechanically (e.g., via belts, gears, transmissions,sprockets, chains, clutches or the like). By using the electricmotors/generators 48 to more precisely control the hydraulic powerprovided to the actuators 26-29, throttling losses can be reduced oreliminated. Additionally, by powering the dual power electro-hydraulicmotor control units 46 a-46 d with both the common pressure rail 55 andthe DC electrical bus 44 as shown at FIG. 5, service power from theactuators 26-29 can be readily regenerated in the work circuit 24.Additionally, braking energy from the propel circuit 22 can be re-routedto the work circuit 24. For example, mechanical energy from braking canbe used to drive the generator which directs electrical power to the DCelectrical bus 44. In this way, engine power management can be enabled.

1. A power distribution architecture for an off-road vehicle, the powerdistribution architecture comprising: a work circuit including aplurality of motion control units configured to be fluidly connected toseparate hydraulic actuators, the motion control units each including anelectric motor/generator mechanically coupled to a pump/motor; anelectrical bus for providing electrical power to each of the electricmotors/generators; and a common pressure rail for providing hydraulicpower to each of the motion control units.
 2. The power distributionarchitecture of claim 1, further comprising a hydraulic accumulator influid communication with the common pressure rail.
 3. The powerdistribution architecture of claim 1, further comprising a first batterycorresponding to the work circuit that is electrically connected to theelectrical bus.
 4. The power distribution architecture of claim 1,wherein the electrical bus is a DC electrical bus.
 5. A powerdistribution architecture for an off-road vehicle, the powerdistribution architecture comprising: a work circuit including aplurality of motion control units configured to be fluidly connected toseparate hydraulic actuators, the motion control units each including anelectric motor/generator mechanically coupled to a pump/motor; anelectrical bus for providing electrical power to each of the electricmotors/generators; a common pressure rail for providing hydraulic powerto each of the motion control units; and a prime mover which drives anelectric generator for providing electrical power to a motor drive of anelectric traction motor of a propel circuit of the vehicle, wherein theprime mover also is coupled by a mechanical power take-off to a pump forpressuring the common pressure rail, wherein the motor drive isconfigured to direct a DC output along a DC power line to a powerdistribution unit, wherein the power distribution unit electricallyconnects the DC power line to the electrical bus and provides DC-DCpower conversion such that the DC electrical bus has a lower DC voltagethan the DC power line, and wherein the power distribution unit allowsfor bi-directional electrical power transfer between the DC power lineand the DC electrical bus.
 6. The power distribution architecture ofclaim 5, further comprising: a first battery corresponding to the workcircuit that is electrically connected to the electrical bus; and asecond battery coupled to the DC power line, the second battery having ahigher voltage than the first battery.
 7. A power distributionarchitecture for an off-road vehicle, the power distributionarchitecture comprising: a work circuit including a plurality of motioncontrol units configured to be fluidly connected to separate hydraulicactuators, the motion control units each including an electricmotor/generator mechanically coupled to a pump/motor; an electrical busfor providing electrical power to each of the electricmotors/generators; a common pressure rail for providing hydraulic powerto each of the motion control units; and a prime mover which drives anelectric generator for providing electrical power to a motor drive of anelectric traction motor of a propel circuit of the vehicle, wherein themotor drive is configured to direct a DC output along a DC power line toa power distribution unit, wherein the power distribution unitelectrically connects the DC power line to the electrical bus andprovides DC-DC power conversion such that the electrical bus has a lowerDC voltage than the DC power line, wherein the power distribution unitallows for bi-directional electrical power transfer between the DC powerline and the DC electrical bus, and wherein the DC power line powers anelectric pump/motor for pressurizing the common pressure rail.
 8. Thepower distribution architecture of claim 7, further comprising: a firstbattery corresponding to the work circuit that is electrically connectedto the electrical bus; and a second battery coupled to the DC powerline, the second battery having a higher voltage than the first battery.9. The power distribution architecture of claim 3, further comprising aprime mover which drives a first electric generator for providingelectrical power to a motor drive of an electric traction motor of apropel circuit of the vehicle, wherein the motor drive is configured todirect a DC output along a DC power line, wherein the DC power linepowers an electric pump/motor for pressurizing the common pressure rail.10. The power distribution architecture of claim 9, further comprising asecond battery coupled to the DC power line, the second battery having ahigher voltage than the first battery.
 11. The power distributionarchitecture of any of claim 1, further comprising a prime mover whichdirects power through a power take-off to a mechanical transmission fordriving propulsion of the vehicle, wherein the prime mover also iscoupled by a mechanical power take-off to a pump for pressuring thecommon pressure rail.
 12. The power distribution architecture of claim11, wherein the mechanical power take-off transfers power from the primemover to the electric motor/generator, and wherein the mechanical powertake-off and the electric generator allow braking energy to be re-routedto the work circuit. 13.-15. (canceled)
 16. The power distributionarchitecture of claim 9, wherein the prime mover drives a secondelectric generator that energizes the electrical bus, and wherein theelectrical bus has a DC voltage that is lower than a DC voltage of theDC power line.
 17. The power distribution architecture of claim 11,wherein the prime mover drives the electric motor/generator forenergizing the electrical bus.